#include<stdio.h>
#include<Windows.h>
#include<time.h>
void main()
{
    int a, b, c, d,i,m,n;
    float p, q;
    srand(unsigned( time(NULL)));
    for (i = 0; i < 30; i++)
    {
        a = rand() % 100;
        b = rand() % 100;
        c = rand() % 5;
        switch (c)
        {
        case 0: printf("%d + %d =\n", a, b);
            break;
        case 1:if (a < b)
        {
                   d = a;
                   a = b;
                   b = d;
        }
               printf("%d - %d =\n", a, b);
               break;
        case 2:printf("%d * %d =\n", a, b);
            break;
        case 3:
            while (b == 0)
            {
                b = rand() % 100;
            }
            printf("%d / %d =\n", a, b);
            break;
        case 4:
            a = rand() % 100;
            b = rand() % 100;
            m = rand() % 100;
            n = rand() % 100;
            c = rand() %4 ;
            while (b == 0)
            {
                b = rand() % 100;
            }
            while (n == 0)
            {
                n = rand() % 100;
            }
            if (a > b)
            {
                d = a;
                a = b;
                b = d;
            }
            if (m > n)
            {
                d = m;
                m = n;
                n = d;
            }
            switch (c)
            {
            case 0:printf("%d/%d + %d/%d =\n", a, b, m, n);
                break;
            case 1:
                p = (float)a / (float)b;
                q = (float)m / (float)n;
                if (p < q)
                {
                    d = a;
                    a = m;
                    m = d;
                    d = b;
                    b = n;
                    n = d;
                }
                printf("%d/%d - %d/%d =\n", a,b,m,n);
                break;
            case 2:printf("%d/%d * %d/%d =\n", a, b, m, n);
                break;
            case 3:
                a = rand() % 100;
                b = rand() % 100;
                m = rand() % 100;
                n = rand() % 100;
                c = rand() % 4;
                while (m == 0)
                {
                    m = rand() % 100;
                }
                printf("%d/%d / %d/%d =\n", a, b, m, n);
                break;
            }
        }
    }
    system("pause");
}